Conventional methods for treating PPDC-impacted solids, such as landfilling, bioremediation, combustion, and thermal desorption, are typically time consuming and/or expensive, and may not always be preferred or adequate for reducing Total Petroleum Hydrocarbons (TPH).
E-beam processing has advantages over conventional methods for treatment of PPDC. In general, e-beam processing can cause chemical and physical changes in various substances by exposure to ionizing radiation in the form of electrons with energies lower than about 10 MeV. This process can have various effects depending on the material being processed, the dosage, or amount of treatment that is being applied. These effects include but are not limited to bond cracking, cross-linking, polymer degradation, sterilization, pasteurization, and vulcanization. E-beam differs from other irradiation processes, most notably because it is highly controllable and can be used without significant residual effects.
Several examples have been reported in the literature for e-beam irradiation of liquid PPDC streams, but none where solids containing PPDC have been e-beam irradiated. For example, PetroBeam reported the treatment of a 12° API heavy crude oil (1.7% wt of S and 6% water) pulsed irradiated at 2 MeV at 50° C. with time-average of 20 and 37 kGy/s and with a total absorbed dose of 360 kGy (residence time ˜13 s). The results showed respectively 17% and 22% conversion of residue having an atmospheric equivalent boiling point >450° C., and a 10-fold reduction on the sulfur content.
Similarly, researchers from Texas A&M University have treated an atmospheric residue (7.4° API, 10.4% asphaltenes and hydrogen to carbon molar ratio H/C=1.47) and reported lower viscosity and higher amounts of distillable material after e-beam radiation thermal cracking at 385° C. for one hour (RTC at 10 kGy) compared to conventional (no e-beam) thermal cracking (TC) at 385° C. for one hour. Percentages of 550° C. residue conversion were 31% for RTC versus 26% for TC. Stability was measured by determining the viscosity over a period of three months, and the results showed that viscosity of the RTC samples was stable whereas the TC increased reaching a plateau after two months.
However, there are no known e-beam methods for: remediating PPDC impacted soil or sediments; treating undesired oily streams (e.g., oily sludge, drill cuttings, tank bottoms, etc.); or high throughput (volume per unit time) and high efficiency (rate and yield of TPH removal or transformation) processes for the application of e-beam irradiation. In addition, there are no known methods that include the recycling or disposal of the converted, mobilized or otherwise transformed PPDC, including gaseous components.
As such, a need exists for improved high throughput and high efficiency e-beam irradiation processing methods for remediating PPDC-impacted solids for beneficial reuse and for recycling or disposing gaseous hydrocarbons resulting from the e-beam irradiation.